[Concepts] Fix parsing of scope specifier in compound-requirements, add more...

[Concepts] Fix parsing of scope specifier in compound-requirements, add more tests for scope specifiers in type-constraints

The code for parsing of type-constraints in compound-requirements was not adapted for the new TryAnnotateTypeConstraint which
caused compound-requirements with scope specifiers to ignore them.

Also add regression tests for scope specifiers in type-constraints in more contexts.